f2fs: add a rw_sem to cover quota flag changes
Two paths to update quota and f2fs_lock_op:
1.
- lock_op
| - quota_update
`- unlock_op
2.
- quota_update
- lock_op
`- unlock_op
But, we need to make a transaction on quota_update + lock_op in #2 case.
So, this patch introduces:
1. lock_op
2. down_write
3. check __need_flush
4. up_write
5. if there is dirty quota entries, flush them
6. otherwise, good to go
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 611cb76..a3c506b 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1255,6 +1255,7 @@
block_t unusable_block_count; /* # of blocks saved by last cp */
unsigned int nquota_files; /* # of quota sysfile */
+ struct rw_semaphore quota_sem; /* blocking cp for flags */
/* # of pages, see count_type */
atomic_t nr_pages[NR_COUNT_TYPE];